Standard baseball bats include wood baseball bats consisting of a single piece of wood, laminated wood baseball bats comprised of multiple solid sections of wood adhered together, and metal baseball bats. A wood baseball bat requires a greater level of skill to use than a metal baseball bat. However, people who are interested in the integrity of the game of baseball, interested in preparing for entry into the professional baseball leagues where wood baseball bats are the only bats permitted to be used, or who prefer the sound and appearance of a wood baseball bat, seek to find wood baseball bats with the best performance and durability features available.
Major League Baseball (MLB) requires the use of wood bats. These bats do not, however, have to be made of a single piece of wood. The MLB rules committee, for example, has approved a wood bat made of four different pieces of wood, each of a different species, glued together.
There have been recent safety concerns with metal bats. Metal bats have a “trampoline” effect when a ball is hit. The metal deforms and bounces back adding a certain amount of unpredictable direction to the ball. Thus infielders, such as a pitcher or a third baseman, can be injured when a high velocity ball comes off a metal bat with a direction that cannot be readily predicted by observing the bat hit the ball. The infielders are hit before they can react. Thus there is a growing movement among Little League and public school baseball teams to require the use of wooden bats.
Single piece wooden bats, however, have their own safety drawbacks. Single piece wooden baseball bats are vulnerable to breaking into two pieces when a ball is hit. The flying piece of bat can injure a nearby player.
A more subtle safety and comfort issue is a single piece wooden baseball bat will “sting” the hands of a batter when a baseball is struck away from the “sweet spot” of the bat. The stinging causes immediate discomfort and could potentially cause long term injury.
A related drawback of single piece wooden bats is that they are limited to having a relatively high weight for a given length of bat. The weight of a bat relative to its length is given by its “drop number”. A drop number is equal to the length of a bat in inches minus its weight in ounces. A 30 inch long bat weighing 27 ounces, for example, has a drop number of 3.
Metal bats designed for children, such as those playing in Little League, will have a drop number as high as 10. The high drop number means that the bat is relatively light for its given length and therefore will be easier for a child to swing. It is difficult to make a single piece wooden bat with a drop number greater than 5. To do so would result in a bat that is too thin and prone to breakage.
Various designs of laminated wooden bats have been proposed to address some of these limitations. Laminated wooden bats comprise bats made from two or more pieces of wood that are adhered together, such as by using glue.
U.S. Pat. No. 813,400 to Buehler, for example, describes a baseball bat made from longitudinal segmental sections of wood glued together. Buehler teaches that the grain of at least some of the sections must be oriented so that it is substantially at right angles to the corresponding tangents of the bat. This unfortunately leads to a substantial amount of wasted stock due to the manner in which the segments must be cut from the original pieces of wood so that the grain in each piece has the proper orientation. Buehler contemplates recovering some of the wasted stock by incorporating it into a bat with the grain parallel to the corresponding tangents instead of at right angles to them (Buehler FIG. 7, item 4), but he concedes that this is an inferior result.
U.S. Pat. No. 2,458,919 to Marsden describes a laminated bat where segments are glued to an axial reinforcing rod subject to the restriction that the grain is approximately radial along the entire length of the bat. This also results in wasted stock for the same reasons as Buehler. The central reinforcing rod may also substantially alter the hitting characteristics of the bat.
Thus there is a need for a method of constructing a laminated bat such that wood is efficiently used given the natural variations in wood grain of the stock. There is also need for a wood bat that can be made with a drop number in the range of 5 to 12 without resulting in breakage of the bat into two or more pieces upon failure.